The present invention relates to a motor-driven compressor.
A motor-driven compressor includes a compression unit, which compresses and discharges a refrigerant, an electric motor, which serves as a drive source for the compression unit, and a motor drive circuit, which drives the electric motor. A conductive terminal electrically connects the motor drive circuit and the electric motor, and a lead wire extends from the electric motor. A connection terminal arranged in a cluster block, which is accommodated in a housing, electrically connects the conductive terminal and the lead wire. Japanese Laid-Open Patent Publication No. 2006-42409 describes an example in which the cluster block is coupled to a stator core of the electric motor.
In a motor-integrated compressor (motor-driven compressor) of the above-described publication, a cluster (cluster block) includes a dovetail projection, and a stator core has an outer surface including a dovetail groove extending along the axial direction of the stator core. The dovetail projection is engaged with the dovetail groove by sliding the dovetail projection into the dovetail groove. This couples the cluster to the outer surface of the stator core.
Shrink-fitting is performed to couple the stator core, which is coupled with the cluster, to the interior of the motor housing. After the stator core is shrink-fitted to the interior of the motor housing, the conductive terminal and the connection terminal are connected in the cluster. When the cluster is coupled to the outer surface of the stator core by engaging the dovetail projection and the dovetail groove like in the publication described above, a clearance is formed between the dovetail projection and the dovetail groove. The clearance allows for adjustment of the position of the cluster to a certain extent. Thus, when the stator core is shrink-fitted to the interior of the motor housing, the conductive terminal and the connection terminal may easily be connected in the cluster even when the conductive terminal and the connection terminal are not located at the proper connection positions.
In the publication described above, however, the dovetail groove formed in the outer surface of the stator core to couple the cluster to the stator core inhibits the flow of magnetic flux through the stator. This lowers the torque of the electric motor.